Some of you may know of PS Audio Paul McGowan's daily missives about various audio topics. He has been writing recently about amplifier power supplies [an excellent long series breaking down the relative merits of linear and switching power supplies], leading in to his recent topic about amplifier power. Today's post, titled Music Math, is especially interesting, because it summarizes the math about amplifier power reproduction of sine waves, spoken language, and music:

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Our musical math would then show us if we need 50 watts to reach 90dB, we need 10 times that amount to reach 100dB! That’s right, do the math. For a 90dB pair of loudspeakers to produce 100dB peaks in your room without clipping the amplifier, you need 500 watts of power.

And then Paul turns to the natural question that any of us on this forum might ask:

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Many of you are asking me if all this is true, which it is, how come my little 10 watt SET amplifier works just fine on my speakers? Are tubes so much better at peaks than solid state that I am getting away with something?

Looking forward to reading that tomorrow.

It should surprise no one that PS Audio is working on an all-new series of switching amos, and so these posts serve a commercial purpose, but they are interesting and I commend them to anyone who might find the topics enjoyable.

"Aside from the amplifier’s superiority by simplicity, there is a more profound reason for using SET amplifiers. The magic predominately lies in the first watt. By magic I mean inner detail and most of the dynamics. For example, a pair of 96dB speakers playing with one watt of power against the average noise floor in your listening room (55dB) is 40 dB of dynamic range. (96 – 55 = 41 dB) Adding a second watt increases the dynamic range by only 3 dB. For every additional 3 dB you need to double your power. This should clearly illustrate that there is over 10 times the dynamic range in the first watt as there is in the second.

This brings us directly to loudspeakers. A typical loudspeaker today is 86 dB efficient with 1 watt. It also usually has a complex crossover that attempts to keep the frequency response and impedance flat. The crossover alone will usually dissipate a significant portion of the first watt as heat before it even reaches the drivers. To reach the same loudness level as the 96 dB speaker will with 1 watt requires over 8 watts on the 86dB speaker. If we used 2 watts on the 96 dB speaker the other would require 16 watts to keep up. If we used 4 watts on the 96 dB speaker the other would require 32 watts to keep up."

@DBC, yep, I know that paper well. That is one reason I am looking forward to Paul's discussion of SET amps. Though in accuracy, the segment you quoted is much more about the qualities of the speaker and crossover excellence, or lack thereof, than it is about any SET magic.

"Many of you are asking me if all this is true, which it is, how come my little 10 watt SET amplifier works just fine on my speakers? Are tubes so much better at peaks than solid state that I am getting away with something?"

DBC's quotes from Steve's paper on the first watt are on target.

Think about the music envelope, the range of signal that you're amplifying, from the most subtle low level information to the peaks.

SET amps are inherently genuine class A, and as such excel at very low level detail resolution. The small details and ambient cues from the recording are all down at these levels, and SET's expose them in a manner on par with the best performing amps regardless of cost. Compare and contrast to standard ss class A/B, where their low level detail resolving ability is masked due to crossover distortion or the feedback required to combat it-you always have to turn such systems up a bit for them to come to life just to overcome their low level detail resolving deficiencies.

But there is some trickery going on at the other end, the signal peaks, and in this case I think us SET users indeed are "getting away with something" mischevious. As these amps (I refer strictly to the SE84C+, as that's what I own) start to clip, the distortion profile is a low order, monotonically decaying pattern (meaning both even and odd harmonics, of low order and rapidly diminishing levels as the order goes up). Under these peak power circumstances the amps electrical output plateaus, but he harmonic distortion content increases, and the "trick" is that we perceive this as increased loudness. In this sense, a SET acts as an ideal compressor when pushed into clipping-at least up to a point. Fortunately, SETs have a ton of wiggle room and can exhibit large amounts of THD before they sound objectionable. Compare and contrast to ss power at clipping: predominantly odd order harmonics that extend much much higher, which is pretty much unlistenable even in minute amounts.

So what we get is excellent detail resolution at the low end, and ear friendly compression at the top end. I think this is why SETs at 85 decibels sound as loud as ss amps at 95 decibels. Throw in some speakers that are sensitive enough to dwell in the first couple watts, and you have a recipe for musical enchantment.

I'll be curious to see what Mr. McGowan has to say tomorrow.

The folks pouring 500 watts into their speakers should buy stock in Phonak (they make hearing aids). What goes around comes around.

I like this discussion, and appreciate the time DBC and ski bum put into responding. And as I said, I am looking forward to Paul's posts on this topic. A couple of things caught my eye, this in particular:

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I think this is why SETs at 85 decibels sound as loud as ss amps at 95 decibels.

I have not had that experience. To me, volume matching is pretty much just that. However, at the same volume, especially a slightly lower one, I find our low-wattage amps much more engaging.

Quote:I think this is why SETs at 85 decibels sound as loud as ss amps at 95 decibels.

I have not had that experience. To me, volume matching is pretty much just that. However, at the same volume, especially a slightly lower one, I find our low-wattage amps much more engaging.

Yes, that particular statement may be an exaggeration, but yes, more engaging is exactly what I'm talking about. More low level detail, more meat on the bones. Level matched, the SETs win the pepsi challenge every time.

Yes thanks.I`ve allways had one of those little personal chessnuts in that volume isn`t allways equal to loudness...more like headroom. An increase in volume does just that, expands the space that the music inhabits, or makes it grow. Yes it does sound louder, but can you make it louder without expanding the volume ? Perhaps amps have a `sweet spot` so thats how you decide which power model is best for your requirements.

Let's not miss the main point, though. There's a dichotomy and we have chosen the low-level rich detail and lush midrange with fine highs full of sparkle, and this is great sound. But, the tradeoff is still there regarding limited dynamic boost and 'oomph' typical of higher powered amps.

Regardless of how sensitive the speakers are, I'm not talking about loudness levels or volume, but a trait which will never be possible in low power tube amp designs. Yet, who cares so long as we get that indescribable sound richness. Its a tradeoff choice and I know we are on the better side of the divide.

Well, I don't really have enough experience and information to say that, and I guess I care. I'm not really sure that speaker sensitivity can't "substitute" for "power in reserve." There may be more than enough power so to speak.

Anyway, ski bum (kindof hate to address you that way!) is right. There are many approaches to the goal of exciting musical playback. I think many here will say if you have the right Decware amp with the right Decware speaker you feel you have power enough.

A 5W SET does not cut the mustard even with 95dB sensitivity loudspeakers!

This then leads McGowan to these calculations, which he acknopwledges are fairly extreme:Quote:

The next set of figures are all based around the same 90dB efficient speaker playing music, but this time measured at a 3 meter distance, meaning 10 watt of sine wave power is needed to give you 90dB as a reference.

Interesting. I just relate to the time I had VTL monoblocks (225 Deluxe, back in the early 90's), a push-pull design with 225 Watts per channel RMS. I recall the level of detail and transparency almost as good as my Mini Torii, but with impressive dynamic capacity to go into peaks.

At the time, my speakers were floor-standing Clements, with a mix of electrostatic ribbons and more traditional drivers for the lower mid and bass frequencies (I don't recall the specs, sorry).

In any event, the music had a lot of presence and you could feel the power coming out of those speakers in typical highly dynamic passages, although that system never really handled the lower frequencies properly.

This is not too much power for SS standards, mind you, but a significant brute in PP tube amplification.

I prefer my Mini Torii in every aspect, except I do miss that reserve of dynamic capacity (oomph!), or power feeling, when some of my classical music passages could take advantage of it.

I imagine the new Torii Monos bring along something of this trait to a new market niche in Decware, a cluster that tends to go away from near-field, headphone and small room close listening, and offers that same wonderful sound quality at a higher dynamic potential.

Today's article didn't say much. Lots of reinforcement for their ridiculously inflated power demands. Anyone with a voltmeter and an Omnimic can objectively disprove their claims.

I think the Tambourines article was pretty straightforward, but I thought what it covered was interesting. But walk me through that disproof with the voltmeter and Omnimic. We're talking about some reasonably intelligent people over there, and while I do believe there is ample room for different approaches, I am not so sure that the role of power in signal amplitudes is an inherent fallacy.beowulf wondered:Quote:

It looks as though Mr. McGowan may be setting this up to push his new amp design on us ... bet it's either some mega watt monster or some technology that acts like a mega watt amp, etc.

Well, yes, that much has actually been overtly stated by McGowan; they're not being coy or deceptive, and the lengthy series on power supplies that preceded the current power discussion was part of it as well. They're working on a series of Class D amps, the first of which I believe will be an integrated amp, and one of which will, per McGowan have specs like this, with more to come:

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Expect a dual mono version in the PerfectWave DAC chassis rated at 350 into 8, 700 into 4 and 1200 into 2. While not optimal it gets us really close and we should be able to come in slightly under $3K with killer sound.

Say what you will about hype, but specs like that, in the price range, will be very appealing to some folks who are not into high efficiency or first watt. Not saying they are right, but a lot of those folks are not convinced we are either. Moreover, one listen to a PWT and/or PWD will show you these are people with real ears who know what they are doing. I personally think we learn more from people who think about and approach problem-solving from a different perspective, while we are less likely to learn something new from people who already agree with us.

They're working on a series of Class D amps, the first of which I believe will be an integrated amp,

So far I have owned Class A 200 watt (MOSFET) and Class D 200 watt (ICE) amps ... these left me wanting more and wondering why everybody was so ga-ga over them. To say the least I was unimpressed and that's what actually started me looking into tubes and how I found Decware is because of my disappointment with SS amps in general (at least the ones I have owned or heard)

But having had both and "if" I had to choose between SS Class A or D, I would take the Class A MOSFET because I think it sounds less SS in comparison ... I guess I just don't get the D thing

beowulf, I never got the D thing either, but I think that has been the entire point of the long series: PS Audio is taking a very thoughtful approach to the use of the technology [McGowan also discussed their decisional process to get to the point of even considering D technology, how they had not planned to return to the amp business after many years of absence, etc.]. I cannot imagine anyone at PS Audio is interested in un-musical amplification.

For me, my experience with Decware—my first tube amps since I was quite young—has been revelatory. Every time I listen to my system, I am very engaged by its musicality. So, as far as I am concerned, anyone advocating this technology has a high bar to clear. Actually, it would take a huge crowbar to separate any money from my wallet for an amp, after what I have been hearing for the last two years. I have four Decware amps, and a fifth on order.

But I am still learning by reading and watching this process. In today's post, Watts Ain't Watts, McGowan doesn't say too much about other amps, but he does start stepping back from some of the more extreme implications of yesterday's wattage calculations:Quote:

All the measurements we described were anechoic chamber measurements: meaning there was no room involved. As soon as you add a room to the mix, the loudness levels at your seat are very close to the loudness levels near the speaker – certainly greater than if the speakers were outside or in an anechoic chamber – the good news is the extremes I showed aren’t quite that dramatic.

I don't think one can have a conversation about amplifier power without considering the full spectrum absorption in any given room... The more sound absorption, the more power is needed to reach a satisfying sound level in your room...

With all this talk about room treatments, a low power SET amp can be right at the margin as far as supplying a wanted volume level AND the substantial fidelity these amps are capable of...

I'm not a big fan of putting more sound absorption in any room... I usually go for less, and hope it sounds right in my room environment... Albeit, it does put more of a burden on you to place the speakers right...

If a rabbit defined intelligence the way man does, then the most intelligent animal would be a rabbit, followed by the animal most willing to obey the commands of a rabbit. -Robert Brault, writer (b. 1938)

Mr. McGowan's claims of increased demands of voice/music over sine waves is a red herring. The whole "crest factor" schtick is marketing flim flammery. An amp is either sufficient (able to reproduce unclipped peaks, which are determined by the source voltage, as dictated by the recording/mastering, and the inherent limits of the medium), or it's not.*

Beowulf is right, this is just a marketing effort for their upcoming amps. McGowan is simply chumming the waters.

Quote (Beowulf): walk me through that disproof with the voltmeter and Omnimic.

Use the volt meter to measure the actual amp power, and the calibrated mic to measure the corresponding spl. I've done it, and achieving specific spl targets takes far, far less power than he claims is required. Peaks at 113db take about 35 measured watts in my system.

* Speaking within the confines of established engineering best practices. The odd logic of SETs does not apply in this case.

This is not meant to sound contrary; I just don't quite see this as simply as you do, nor do I see a different point of view as so crassly commercial and without intellectual merit as to be written off as "chumming the waters." You're talking about a guy who has acknowledged contributions to high fidelity engineering, who has developed some of the top equipment of this and previous eras, who is on his company's forums day and night, and who responds to emails directly within hours. His equipment is used side-by-side with Decware users on this forum, and to rave reviews on both. He has earned better. Obviously, no one is required to respect anybody, but if you don't at least give the benefit of attentiveness to someone who might actually know what he is talking about, then you aren't going to learn as much about that topic.

ski bum wrote:Quote:

An amp is either sufficient (able to reproduce unclipped peaks, which are determined by the source voltage, as dictated by the recording/mastering, and the inherent limits of the medium), or it's not.*

Actually, I think you and McGowan are in perfect agreement on that. I think the difference between the two of you might be as conceptually simple as how one approaches measuring the starting point, because there is not a whole lot of denying the math, once you have the starting point.

While I agree that terms like crest factor can be just packaging of concepts that either are or aren't valid [though see the last comment on the post cited below; there is actual math there], I learned a long time ago that mere amp measurements as you describe don't actually tell you what it takes to reproduce the levels of live music, even if that live music is as subdued as a whispering female singer. As for chumming the water, I am just as much a cynic as the next guy, perhaps even more so, but this topic is about much more than just advancing a marketing ploy. PS Audio is hardly alone in this viewpoint that more watts might be needed than thought to reproduce certain dynamics in music. Measuring how loud your watts currently can make a speaker sound doesn't mean a whole lot to me. Would that it were as simple as you make it sound.

But measuring a high SPL does not mean you are measuring unclipped output with sufficient headroom to reproduce the next 3db. And that is what this is all about. Not just can you go loud, which BTW, my Toriis and ERRs do quite well, but can your amp and speakers handle the dynamic range once the floor of what you are listening to has been established.

All McGowan has said is this: if it takes a certain amount of power to achieve X db of sound level, then it takes Y more power to achieve the unclipped dynamic range necessary for the type of music one may be playing. That's really it. And if you go back and read Music Math with an open mind, including some of the back and forth comments below the post, you will see people engaged in asking very open and candid questions about high power versus headroom, other proponents of high power, proponents of low power, etc. Calling this chumming or flim-flammery is really unfair to the people engaged in the discussion. You may not agree with them, but that doesn't make them dishonest. [Cable and capacitor snake oil, anyone? I used to think so, until I learned to hear otherwise.]

Steve has been called a master marketer, even a huckster, in other forums, but we have reason not to accept that characterization. We took the time to learn otherwise. We might be willing to give the same thoughtfulness to other respected people, even if their perspective is very different. But if we cannot do that without name-calling, then I would submit this thread has probably run its course. Oh well, I thought the discussion was interesting; over there, it still is. I can enjoy it there, and still revel in my Toriis and ERRs.

The fact that this is marketing is established in the first installment of the series, quite explicitly. I'm not making it up. You'll have to pardon my colorful language. But boilerplate engineering rationale to justify a sufficient amp does not make for good ad copy, does it?

They are making claims without providing evidence, and in one case their claim is easily falsified. That's not a good start. By reading this series you would think they are about to re-invent the wheel. They are covering a lot of technical ground in a cursory fashion, which appears to be an effort to confuse and lead the less informed reader to believe that only their new, mega-watt amp will suffice for their needs. In reality, it will be one amp among many of similar technical performance. It will probably be great, too. And it will come with a PS Audio sized price tag. And then they'll ask if you would care for a $2000 A/C cord (without which you will never know the true grandeur of your new kit).

Yeah, no thanks. Respect is earned, not given unquestioningly, particularly in matters of fact, which audio reproduction falls into. I can forgive Steve, he's a home town homie putting food on the table for his family. His products are value leaders in their niche. Even his zen styx are reasonably priced (I roll my own, and I would charge more of a markup than they do). PSA are by and large magic wire snake oil vendors I have no particular allegiance to.

Again, lets not loose perspectives here. The objective being proposed by McGowan is to (essentially) provide optimum headroom for all possible music passages requiring it. But, he does not discusses (yet) the tradeoffs involved.

Plenty of headroom is just one aspect of sound quality. With the required higher power levels, usually there's the tradeoff of transparency. If we believe in the low power-high resolution/transparency approach, increasing power so much will definitely affect and reduce these traits.

I rather have a transparent, lush, beautiful sound at low power levels, than plenty of oomph! and not getting the same quality sound.

This is not new, as this dichotomy has been in this business forever, with SET followers and high-power enthusiasts.

The issue is, so far, nobody has been able to have their cake and eat it too. It's either of the two objectives, not both. BTW, an achievable compromise is a well designed tube Push Pull amp.

Some people in this forum prefer the Super Zen, others are happier with the Torii MKIII, and so are those owning in-between iterations. Oomph! (for lack of a better term), is great IF you already have (and get to keep) all the other (more important, to me at least) attributes.

I'm sure there are some ultra mega-bucks SS designs coming very close to this ideal, in systems with wonderful and complicated loudspeaker designs, but do they really sound as good as a well designed SET?

I tell you what. The most expensive PS A cords are half what ski bum indicates, and can be bought at half that again used, etc. I've tried them, and after trying them, I haven't liked any other power cords nearly as much to settle, so I've decked my system with them and have never been happier with my system sound. I've been poorer as a result, but that's a choice. I think what these do to Decware components elevates the performance past the level that upgrading to more expensive components may take your system. Just a supposition on my point because I haven't bought the more expensive components, but I'm not going to, with these cords the Decware pieces just shine and delight.

It's not snake oil, in my opinion. Is it expensive stuff? Definitely. But they've transformed my components in very positive ways.

As for power levels, I say who cares what's ideal, what the limits of science applied here are, etc. If you follow the advice of the manufacturer regarding component compatibility you can find wonderful sound, loud enough indeed. Those final percentages of what is possible. . . those will always be on the cutting edge and require deep pockets to have excellent sound as well as all the other characteristics. Fly that high to the sun with caution.

As for power levels, I say who cares what's ideal, what the limits of science applied here are, etc. If you follow the advice of the manufacturer regarding component compatibility you can find wonderful sound, loud enough indeed. Those final percentages of what is possible. . . those will always be on the cutting edge and require deep pockets to have excellent sound as well as all the other characteristics. Fly that high to the sun with caution.

I agree with this completely Lon. To me, what's going on over at PSA with Paul's posts is and was originally offered as an interesting set of discussions about power, signal, and amps. It is interesting, as is today's post about why the real world sounds different than what the math seems to suggest is required. One need not agree with any or all of it. But if it is treated as adversarial, merely because it might not be coincident with one's views, then I suppose it falls out of the interesting bucket. That's okay. I would rather discuss it as a topic of interest, not a topic of binary opposition. Interesting if we poke on it, and it allows us to poke on ourselves, less so if we have to prove one right and another wrong. In other words, this need not be a zero sum game.

And oh yeah, +1 on the power cords. The PSA power cords are simply amazing, whichever ones you can find and afford. But they are physical brutes. And beware of the Asian fakes, especially on fleabay.

@ski bum: on the marketing side, I completely agree, and I think I was pretty clear when I first posted that the discussion was part of a ramp to a new amp product line. But the fact that information might have a marketing purpose is also not a proof of its invalidity; it just means we have to keep it in perspective.

@Fireblade: completely agreed. Perspective is the name of the game. McGowan's discussion has been heavily focused on what might be broadly referred to as headroom. I love my Decware stuff, love what I hear from my system, am not looking to trade to some mega-amp, but as someone who also thinks about how the sound gets out of this wonderful system, and someone who appreciates other PSA products, I just found it all darn interesting.

P.S. Love the word lush. I think it is part of the 3-D experience my system produces. Anyone looking for lush, play this girl's music; you'll know if your rig is producing it. BTW, I cannot recommend the Linn recordings highly enough. Great stuff. The recent Dunedin Consort release of the Bach John Passion is extraordinary. If you've got the DAC, it's got the rez.

You're right about the fake PS A cords, gotta be on the lookout for those.

I think that McGowan's current goal is to come up with amps that are tailor made for the Perfctwave and Nuwave DACs, and I bet that they'll be optimized to work wonderfully with those and will sound GREAT. But they won't be Decware amps. . . and they really won't even be competing for the same market share.

Wait, Pale Rider...the "girls music" you are referring to is the Linn Records album right?? I'm being a bit slow this Saturday evening, sorry!

I spent the past week trying to figure out an issue I was having with JRiver on my computer...and today (after some back an forth with some folks on the JRiver forums) I figured it out!

BTW I downloaded some sample Hi-Rez music from HD tracks and it sound pretty fantastic through my DAC...man! I was just listening to some Radio Head (from my own library) and I haven't had time to a/b it with the CD, but playing through my computer with JRiver and JPlay I don't think it's sounded better.....hmmm this computer audio realm is sounding very sweet so far....more to come

McGowanThere are a lot of variables going on as you would imagine. I’ve been to enough listening environments to have heard the gamut from great sounding SET systems of only a few watts to mega systems of many watts and they are all different.

Some of the SET setups I have heard sounded great on certain kinds of music but dreadful on others.

Today's post pretty much equals ... SET "dreadful" on anything other than Jazz and Classical.

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McGowanI’ve noticed, for example, that many SET owners choose their music carefully rarely playing anything with high average value – like my Pink Floyd example – and concentrating their selections on high peak value music like classical or jazz.

Are you guys choosing your music "very carefully"? Because according to Paul if you aren't ... it probably sounds like crap!

Heh, I already wrote Paul about that. Because I listen to Floyd all the time! One of his faves, Wish You Were Here, is a regular SACD on my system. This bit also seems somewhat contradictory of his point the other day about compression, in which WYWH was featured, and it also seems inconsistent with the notion that classical music has dynamics requiring megawatts.

I disagree with the statement that SET is only suitable for Jazz and classical.

It took me lots of patience and tube-rolling to get my SE setup to work with all genres of music.My tube rolling adventures came to an end when I finally rolled in the Brimar 5R4GY rectifier in my system.

Now I have the lush tube warmth required for jazz vocals.Bass wise, I have a tight low end with vibrational impact sufficient to shake one's molars if I play Japanese Taiko drums music.For the treble, cymbals have "zing", decay and acoustic guitars or harps can bring tears to the listener.Classical music pieces are also clean and linear sounding.

IMHO, the ultimate test would be modern Pop music which places sonic requirements on the bottom end all the way to the top end.Contemporary pop music by Madonna sounds great on my SE system.

In today's post, SET Down For This One, McGowan starts his deconstruction of what he calls the "SET mystique." The advantages of single-ended output, second order harmonics clipping distortion, and high voltage are briefly discussed, but there isn't much else than that. I am returning to my playlist from last night:

He's still doing the cursory survey of a complex topic, and repeating some gerealizations which may or may not be the case. He's actually correct on the class A thing. The voltage thing is a bit more complicated, and I'll be curious to see if he veers off into being nonlinear into real speakers, or talks about apparent increased dynamic power (which for SETs is more likely relating to their overdrive characteristics...which us SET users try to minimize by choosing appropriate speakers in the first place).

Today's post, High Voltage, starts to get interesting around tubed amlification advantages:Quote:

But if the device has a power supply of 300 volts, like many tubes do, then our linear region just went from 7.5 volts to 75 volts and that’s a lot of region in anyone’s book.

This is one of the reasons why all PS Audio products are so power supply intensive. Not only do we subscribe to bigger is better, but higher as well. Our typical operating voltage for our DACS and preamps is not the standard 24 to 30 volts, but 60 instead. This gives PS source products twice the linear region of most solid state devices – yet far lower than a tube would have.

From our perspective, if you can keep the signal you want well within the linear boundaries of the amplifying device, you’re fine – so 15 volts of linear region is far more than the maximum output signal is going to get to – hence we stick with that.

The additional linear region of a tube is wasted once you pass over a certain level. Wasted, that is, on linear performance – but valuable on another front – headroom in an amp.

With all his previous ramblings about tube amps not cutting the mustard - he brought his new high powered amp to a shootout at Arnie Nudell’s home (founder of Infinity and Genesis) and Paul admitted that the new PS Audio design was out done by ... guess what???

A tube amp!

Well at least he had the balls to admit it ... he's rolling up his sleeves and trying again ... maybe he should should incorporate some tubes in it this time

So his big hyphex (or whatever) class D, with great specs, got subjectively bested by a ten year old pp tube amp. It's kind of an apples to oranges comparison, and not too surprising. Makes me think he's spinning his wheels and going nowhere.

Maybe he should call Bob Carver to help him alter the transfer function of his squeaky clean, high headroom amp to more closely mimic the tube amp, if that's really his goal. (I thought he was more interested in building an amp capable of unclipped tambourine hits requiring thousands of watts to cleanly reproduce. Maybe he should take some marketing classes from Bob, too.)